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#1 2012-10-10 14:47:35

Registered: 2012-10-10
Posts: 1

Disable laptop monitor at startup (when external monitor is connected)

I'd like to disable my laptop monitor at startup (when an external monitor is connected), but make it available in X.

By default, my boot looks like :
* Grub2 displays only on my external monitor (at maximum resolution)
* Kernel displays only on my external monitor (maximum resolution)
* udev (I think) is started and turns on my laptop screen. Then I get the same display cloned on both my monitors, at laptop resolution (leaving me with a small resolution on my external monitor).

I can disable the laptop monitor by setting


in /etc/default/grub, which is perfect, except I cannot use my laptop screen in X anymore (it is shown as disconnected by xrandr). And I suspect I can't see anything if I disconnect my external monitor (which I do frequently).

I've seen other people with the same problem (especially … n-806714/), but no answer.

I'm using an early KMS start with the intel driver (i915), with Kernel 3.5.6-1-ARCH.

Is there a way to reclaim a monitor after boot ? Or is there another way to disable a monitor at startup ?

Last edited by ThomasQ (2012-10-10 15:08:20)


#2 2017-10-22 10:45:59

Registered: 2012-05-14
Posts: 339

Re: Disable laptop monitor at startup (when external monitor is connected)

Is it possible now after 5 years?
I have a laptop connected to an external monitor with HDMI and I would like to see the boot process only on the external monitor when it is connected.
Now it flickers between the external and internal monitors and the greeter SDDM is displayed on both monitors.
After login this startup script (/usr/local/bin/


IN=$(xrandr | grep "eDP" | grep " connected" | sed -e "s/\([A-Z0-9]\+\) connected.*/\1/")
EXT=$(xrandr | grep "HDMI" | grep " connected" | sed -e "s/\([A-Z0-9]\+\) connected.*/\1/")

if (xrandr | grep "$EXT disconnected"); then
    xrandr --output $EXT --off --output $IN --auto
    xrandr --output $IN --off --output $EXT --auto

solves the problem.

Adding /bin/bash /usr/local/bin/ at the end of /usr/share/sddm/scripts/Xsetup, I've managed to disable the internal monitor if the external monitor is connected before the execution of SDDM that now appears only on one monitor.

In any case it will be nice to be able to identify the connected monitor during the boot phase (as windows 10 on the same laptop does).

Last edited by Xwang (2017-10-22 11:16:05)

I'm still learning English so please excuse me if my English is not good enough and feel free to correct me via PM if you want.


#3 2017-10-22 12:48:01

Forum Moderator
Registered: 2012-10-16
Posts: 19,240

Re: Disable laptop monitor at startup (when external monitor is connected)

Thanks for the relevant contribution,  however we'd rather see new threads created that reflect the current state of affairs instead of necrobumping 5 year old threads. Please refrain from doing so in the future: … bumping.22



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